From my perspective, we should spend. Regardless of our squad strength or depth, this pandemic has created market conditions that are conducive to bargain hunting. Clubs with the financial strength to take advantage will find willing sellers and less competition for their targets. For example, look at Chelsea, under normal market conditions, I am not sure that Leverkusen is amenable to selling Havertz at all, never mind at a price below €100m.
If United had access to additional funds (ignore the drawdown on their credit line a few months ago, which I suspect was done to smooth out cash flow issues with the loss of match day revenue), I think this is the summer to spend as much as is financially reasonable.
There will be players who will be available at lower prices than would be expected under normal market conditions and others who will be available who otherwise wouldn’t be at all. This is the time to flex United’s (FFP-compliant) financial muscle, not shrink back and let impaired clubs catchup and compete for targets next year.